Tower cranes



June 27, 1967 P. DURAND 3, 7,

TOWER CRANES Filed Oct. 24, 1965 2 Sheets-Sheet 'l June 27, 1%? P.mun/m0 3,327,871

TOWER CRANES Filed Oct. 24, 1965 2 Sheets-Sheet 2 //v l E/V role /D/EEE0 02 4 ND A Tr YJ.

United States Patent 3,327,871 TOWER CRANES Pierre Durand, Lyons,France, assignor to Richier (Societe Anonyme), Paris, France Filed Oct.24, 1965, Ser. No. 504,441

Claims priority, application France, June 14, 1965,

46,101, Patent 1,449,764

4 Claims. (Cl. 212-46) The raising of a tower crane is generallyperformed through the incorporation in the tower of extensionsconstituted by independent sides or else by systems including severalsides.

For the positioning of such extensions, the conventional method used forhoisting loads through the crane is resorted to, since it requires noauxiliary mechanism. Said conventional method cannot however be usedunder all circumstances, since, by reason of the location of the cranewith reference to the surrounding obstructions, the jib cannot alwaysoperate on all the sides of the tower. It is true that arrangements havebeen proposed for erecting the crane while leaving the jib in astationary position but such arrangements are intricate and oftenrequire a succession of intermediate steps and furthermore they are ofinterest only in the case of small and medium-sized cranes.

In the case of large cranes, the most advisable arrangement consists inresorting to a short auxiliary jib provided solely for such purposes andwhich is located generally at the upper end of the tower and is adaptedto revolve around a vertical axis, so as to serve all the sides of thetower. Although such an arrangement is very convenient, yet it isexpensive, since it requires the use of a second winch or at least of asecond winch drum, said second winch or winch drum serving solely forthe erection of the tower.

Now, my present invention allows eliminating this second winch or winchdrum in cranes provided with a short jib to be used chiefly for addingextensions to the tower or removing such extensions for increasing orreducing correspondingly the height of the tower.

To this end, I engage the free end of the hoisting cable over the shortjib which latter serves selectively for anchoring said free end duringthe conventional hoisting of loads and for guiding the cable during thehoisting of the extensions suspended to said cable at its free end.

In the first case corresponding to the conventional operation of thecrane, the short jib forms the stationary point to which the free end ofthe cable is anchored. In the second case, corresponding to the hoistingof the extensions, the cable passes freely over the short jib and itsfree end may serve for engaging an extension or for engagement with theshort jib after passing over a tackle carrying a hook by which anextension is suspended.

My invention will be readily understood from the reading of thefollowing disclosure, reference being made to the accompanyingdiagrammatic drawings illustrating by way of example and in anon-limiting sense a preferred embodiment of my invention. In saiddrawings:

FIGS. 1 and 2 are side views of the upper part of a tower cranerespectively during normal working periods and during the hoisting of anextension with a view to increasing the height of the tower.

In said figures, 2 designates the crane tower, 3 its conventional jibserving for the hoisting of loads, 4 the counterjib and 5 the shortupper auxiliary jib serving for the raising of extensions such as 6 tobe incorporated with the tower, so as to increase its heights. 7designates the hoisting winch of which the cable 8 passes in successionover the pulleys 9, 10, 11 and over the pulleys and tackle secured tothe carriage 12.

According to my invention, the cable passes in its section lying beyondthe carriage 12 over three pulleys 13, 14a, 14b of which the two latterare carried by the short jib provided with a terminal guide 15 engagedby the cable 8 the free end of which carries a hook 16.

When the crane is being used conventionally for hoisting loads, saidhook 16 bears against the underside of the guide 15, that is against theend of the short jib. The rotation of the winch produces consequently,according to the direction of said rotation, a rising or a sinking ofthe hoisting hook 17; this corresponds therefore to the normal operativecondition of the crane as illustrated in FIG. 1.

When it is desired to increase the height of the crane throughincorporation of extensions 6, the same winch 7 is used, but thehoisting tackle has been operated so as to engage the underside of thecarriage up to a locked position for which the hoisting hook 17 issecured to said carriage, so that it cannot sink again. A rotation ofthe winch in the opposite direction, that is in the downward directionresults in a sinking of the hook 16 secured to the end of the cable 8.From said hook 16 may be suspended as illustrated in FIG. 2 an extension6 the hoisting of which is effected by making the winch turn in thedirection corresponding to upward movement.

The same winch 7 serves thus for hoisting selectively loads andextensions.

Obviously, my invention is not limited to the sole embodiment disclosedhereinabove by way of example and it covers in contradistinction all themodifications thereof falling within the scope of the accompanyingclaims. In particular, the free end of the cable may, beyond the pulleyat the end of the short jib, pass over the pulley of a block carrying ahook from which an extension may be suspended, the cable passing beyondsaid pulley towards an anchoring point at the end of the short jib, soas to form thus a two-sided tackle.

What I claim is:

1. In combination with a crane tower adapted to incorporate extensionsincreasing its height, a main jib carried by the tower, a short jibcarried by the tower, a carriage carried on the main jib for lengthwisemovement along the main jib, a winch, a single cable controlled by saidwinch and trained about the carriage to form a depending load-hoistingloop beneath the carriage, said single cable extending over the outerend of said short jib, and hoisting means carried by that portion of thecable which extends over the outer end of the short jib, said hoistingmeans being movable vertically relative to the main jib so as to movetower extensions vertically relative to the main jib.

2. Apparatus as claimed in claim 1, said short jib being horizontallyswingable relative to said main jib thereby to permit horizontalmovement of said tower extensions relative to said main jib.

3. Apparatus as claimed in claim 2, and means for selectivelyindividually fixing the vertical position of said hoisting means andsaid hoisting loop to allow operation of either independently of theother.

4. Apparatus as claimed in claim 1, and means for selectivelyindividually fixing the vertical position of said hoisting means andsaid hoisting loop to allow operation of either independently of theother.

References Cited UNITED STATES PATENTS 2,463,394 3/1949 King 254-188FOREIGN PATENTS 1,296,475 5/ 1960 France.

775,128 5/1957 Great Britain.

EVON C. BLUNK, Primary Examiner. H. c. HORNSBY, Assistant Examiner.

1. IN COMBINATION WITH A CRANE TOWER ADAPTED TO INCORPORATE EXTENSIONSINCREASING ITS HEIGHT, A MAIN JIB CARRIED BY THE TOWER, A SHORT JIBCARRIED BY THE TOWER, A CARRIAGE CARRIED ON THE MAIN JIB FOR LENGTHWISEMOVEMENT ALONG THE MAIN JIB, A WINCH , A SINGLE CABLE CONTROLLED BY SAIDWINCH AND TRAINED ABOUT THE CARRIAGE TO FORM A DEPENDING LOAD-HOISTINGLOOP BENEATH THE CARRIAGE, SAID SINGLE CABLE EXTENDING OVER THE OUTEREND OF SAID SHORT JIB, AND HOISTING MEANS CARRIED BY THAT PORTION OF THECABLE WHICH EXTENDS OVER THE OUTER END OF THE SHORT JIB,